How to get a right click coordinates in 3d_view
Get screen from context.screen or context.window.screen

Get the clicked area by looking at area coordinates, of each area, in the screen returned from context.screen or context.window.screen. Used the latter in example below, my tests suggest could use either.   The region can be obtained from the area.  

    if event.type == 'RIGHTMOUSE' and event.value == 'PRESS':
        screen = context.window.screen # or context.screen
        def get_click_area():            
            for a in screen.areas:
                if (a.x &lt; event.mouse_x &lt; a.x + a.width
                and a.y &lt; event.mouse_y &lt; a.y + a.height):
                    return a
        a = get_click_area()
        print("Right Clicked in %s area of screen %s" % (a.type, screen.name))


as mentioned in my comment, get_3d_area_region() above, will only return the first matching area it finds in the bpy.data.screens collection. For the default file will be bpy.data.screens["3D Full View"].areas[1] every time.